Last week we announced the release of Google AdMob SDK 6.0 with Ad Network Mediation. We’ve noticed some confusion on how to use a mediation ID instead of a publisher ID, so we’d like to explain the difference between the two.

A publisher ID is generated after adding a site/app and is used to request ads from the AdMob network. A publisher ID can request banners as well as interstitials, giving you the ability to use the same ID throughout your application to get AdMob ads. However, for better reporting, we still recommend that you use a different publisher ID for each ad placement.

A mediation ID is generated after creating a mediation placement. A mediation ID is used to retrieve the mediation configuration from the server so the AdMob SDK can make ad requests to other ad networks on your behalf. Unlike a site/app, a mediation placement requires you to define an ad format, for example a 320x50 banner. Trying to request an interstitial ad with a 320x50 banner mediation placement (and vice versa) will result in the following error:

  • iOS - Failed to fetch interstitial ad: Unable to request an interstitial when server configuration was for kGADAdSizeBanner.
  • Android - onFailedToReceiveAd(There was an internal error.)

Therefore, you’ll need to create multiple mediation placements if you want to use banners and interstitials in the same application with mediation.

Feel free to post any questions regarding the AdMob SDK or ad network mediation to our forum. Even better, if you’d like real-time responses, join us at our upcoming office hours hangout session.